JSFiddle - React, Tailwind, and code Playground

HTML

<!--based on code from http://demosthenes.info/-->

<video muted autoplay loop poster="polina.jpg" id="bgvid">
    <source src="http://www.w3schools.com/html/movie.ogg" type="video/ogg">
    <source src="http://www.w3schools.com/html/movie.mp4" type="video/mp4">
    <object data="http://www.w3schools.com/html/movie.mp4" width="320" height="240">
      <embed width="320" height="240" src="http://www.w3schools.com/html/movie.swf">
    </object>
</video>

CSS

html,
body{
    padding: 0;
    margin: 0;
    height: 100%;
    width: auto;
}

video#bgvid {
    position: fixed; right: 0; bottom: 0;
    min-width: 100%; min-height: 100%;
    width: auto; height: auto; z-index: -100;
    background: url(polina.jpg) no-repeat;
    background-size: cover;
}